N-heterocyclic carbene-catalyzed decarboxylative cross-electrophile coupling to access sterically hindered ketones†

Abstract

Although radical NHC (nitrogen-heterocyclic carbene) catalysis has emerged as a powerful strategy for constructing carbon–carbon (C–C) bonds to generate value-added ketones from carbonyl compounds including carboxylic acids and aldehydes, great advances were generally focused on redox-neutral NHC catalysis and oxidative NHC catalysis until now. Cross-electrophile coupling reactions as powerful tools for forming C–C bonds avoiding using preformed carbon nucleophilic organometallic reagents have not been well developed by radical NHC catalysis. Here, we demonstrate that nitrogen-heterocyclic carbene (NHC), in conjunction with manganese (Mn), can promote the cross-coupling of aromatic acids or derivatives with a wide array of broadly available electrophiles to deliver various sterically bulky ketones with high yields. In addition, its utility in the concise synthesis of biologically active compounds is further highlighted.